1. Field of the Invention
The invention relates to a hand pliers for assembly purposes, more particularly for the assembly of pipe connections at pipe systems, said pliers comprised of two limbs which are rotatably connected to one another via a first link joint and which by means of this link joint are divided into an assembly limb and a handle limb, wherein the first handle limb is divided into a lever away from the handle and into a lever close to the handle, and wherein these two levers are rotatably connected to one another by means of a bolt via a second link joint, wherein a tension wheel and a ratchet wheel with external toothing connected torsionally proof to it are pivotably arranged side by side on the bolt in axial direction, and wherein the tension wheel engages into a tension means that connects both handle limbs to one another, and wherein a spring-loaded dog ratchet is arranged at the lever near the handle, said dog ratchet engaging into the ratchet wheel in such a mariner that when the lever near the handle makes a locking movement the ratchet wheel and the tension wheel execute a rotation that causes the closing of the pliers, with a spring-loaded arrest ratchet being provided for which also engages in the ratchet wheel and permits a rotation of the ratchet wheel on closing the pliers, but which prevents its rotation in the opposite direction.
2. Description of the Related Art
A hand pliers of this type is known from printed publication DE 43 32 710 A1. Hand pliers of this type are utilized in the assembly of pipe systems, viz. for the manufacture of sliding sleeve-type pipe connections. In prior art, a spring-back of the handle limbs on clamping the pliers is prevented in that the ratchet wheel—as described in printed publication DE 43 32 710 A1—is provided with a ratchet toothing extending over its entire circumference into which a spring-loaded arrest ratchet comes in engagement. The toothing is so configured that a rotation of the ratchet wheel on clamping the pliers is admitted, though a counter-rotation is prevented. The arrest ratchet is swivel-mounted at a bolt and is brought into engagement with the ratchet wheel by way of spring loading.
Difficulties arise on releasing the arrest ratchet from the ratchet wheel if pipe systems with major nominal widths are mounted. It becomes evident that so high assembly forces may occur during this process that the arrest ratchet gets stuck in the ratchet wheel and cannot be detached any longer.